This invention relates to a process for hydrogenating unsaturated materials using a carrier-supported heterogeneous catalyst system. In accordance with another aspect, this invention relates to a process of preventing or reducing the rate of catalyst deactivation during hydrogenation of olefinic materials that contain contaminants and catalyst poisons. In accordance with a further aspect, this invention relates to a process for the hydrogenation of olefin polymers, especially diene-containing polymers, in the presence of a heterogeneous catalyst system in a fixed-bed reactor wherein hydrogenation is carried out in the presence of alcohol to reduce or substantially eliminate catalyst deactivation due to contaminants present in the hydrogenation feed.
There are known two types of catalysts which are useable for the hydrogenation reaction of polymers, namely (1) the so-called Ziegler type homogeneous system catalyst, and (2) carrier-supported catalysts in which a metal such as nickel, palladium, ruthenium, or the like, is supported on a carrier such as carbon, alumina, silica, silica-alumina, diatomaceous earth, and the like. Catalysts composed of metals of group VIII of the Periodic Table supported on a refractory oxide carrier have generally been used to catalyse hydrogenation of the carbon-carbon double bond present in various unsaturated materials, especially olefin polymers and particularly conjugated diene polymers. The hydrogenation of diene-containing polymers, such as butadiene-styrene copolymers and the like, yield substances of greater saturation and consequently greater stability when used for certain applications. The heterogeneous catalysts which are used in the fixed-bed reaction system often encounter catalyst poisoning problems due to the presence of various contaminants contained in the hydrogenation feed.
There is a continuing effort to develop improved processes to selectively hydrogenate unsaturated materials, particularly olefin polymers and especially diene-containing polymers, to produce polymeric products having desirable properties. The present invention is directed to a process of preventing or reducing the rate of catalyst deactivation during hydrogenation of olefinic materials, particularly diene polymers, containing contaminants and catalyst poisons.
Accordingly, an object of this invention is to provide an improved process for the hydrogenation of unsaturated polymers using heterogeneous catalyst systems.
Another object of this invention is to provide an additive or inhibitor to prevent or reduce the rate of catalyst deactivation during hydrogenation.
Other objects, aspects, as well as the several advantages of the invention will be apparent to those skilled in the art upon reading the specification and the appended claims.